Interchangeable contact extension



Aug. 13, 1929. pA v b 1,724,771

INTERCHANGEABLE CONTACT EXTENSION Filed Sept. 28, 1927 8 5' 0:7 5 3i 5 6 E; 7 a. 7 7 7 [1 2 7 F196 gg .5

Patented Aug. 13, 1929.

UNITED STATES FRANS ROBERT PAIVIG, OF RAISIO, FINLAND.

INTERCHANGEABLE CONTACT EXTENSION.

Application filed September 28, 1927, Serial No. 222,644, and in Germany April 2, 1927.

This invention relates to interchangeable contact extensions for the pole springs of flash lamp batteries of that type in which both pole springs appear at one end of the battery, one being intended for direct contact with one of the terminals of the incandescent bulb, while the other is intended to make contact with a push button or other type of switch associated with the flash light casing, and which in turn may be manipu lated at will to make contact with the other terminal of the incandescent bulb, thereby closing the circuit through said bulb.

Flash lamp batteries of the type indicated 1 are manufactured in such large quantities that there is great chance for imperfections in said batteries passing unnoticed. Particularly, is this true of the pole springs which are frequently found, even in a fresh battery to be laterally deflected through slight defects in their manufacture or assembly so that when placed in the flash lamp casing, such battery fails to make good contact either with the incandescent bulb or with the switch mechanism, so that the I flash lamp fails to operate satisfactorily.

The present invention has for its object the provision of auxiliary contact members which may be placed upon the pole springs and which function in such a manner as to avoid failures in the operation of the flash lamp due to inherent defects in the pole springs.

A further object of the invention is to provide contact extensions which may be operably positioned instantly and without the use of tools and which may be interchangeably employed upon fresh batteries, so that one set of contact extensions will outlast any number of batteries.

Still another object of the invention is to provide pole spring extensions of so wide an area as to assure contact with the incandescent bulb or with the switch mechanism regardless of the degree of lateral deflection of the battery pole spring and which at the same time is provided with buffers of insulation material adapted to coact with the sides of the flash light casing, either to correct the lateral bias of the pole spring if it is so great as to normally come into con tactwith the side of the casing, or to prevent any accidental contact between the conductive part of said extension and the casing in the use of the device.

Other objects of the invention will a pear as the following description of a prefzarred embodiment thereof proceeds.

In the drawing in which similar reference characters are used to denote the same element in the several figures,

Figure 1 is a plan view of a flash lamp battery showing one form of my pole spring extension applied thereto.

Figure 2 is a similar view showing another form of pole spring extension.

Figure 3 is a side elevation of flash lamp battery of the type to which the present invention appertains.

Figure 1 is a similar view of the flash lamp battery showing the form of the invention illustrated in Figure 2 applied to one of the pole springs, and that form of the invention illustrated in Figures 5, 6 and 7 applied to the other pole spring.

Figures 5, 6 and 7 are respectively an end elevation, a side elevation, and a bottom view of a modified form of the invention particularly adapted to use withthe switching mechanism illustrated and described in my companion application No. 1,590,5 i1 granted June 26, 1926.

Referring now in detail to the several figures, the numeral 1 represents a flash lamp battery of well known and conventional construction having the pole springs 2 and 3 projecting from the upper end thereof. Said pole springs are in the form of flat leaf springs angularly disposed, one of said springs being adapted to touch a terminal of the incandescent bulb, not shown, used with the flash lamp and the other to make cont-act with suitable switching mechanism, not shown, which in turn makes contact with the other terminal ofthe incandescent bulb when operated.

On account of the enormous quantities in which flash light batteries of this type are produced defective pole springs are commonly encountered, the defects usually consisting of lateral deflection of one or the other of said pole springs so that it does not come up into good contact with the bottom terminal of the incandescent bulb but Cir sometimes misses the bottom terminal and makes contact with the side terminal. Occasionally, the lateral deflection of the pole spring is so great that when placed in the casing ittouches the side thereof and short circuits the battery.

Adverting first to that form of interchangeable contact extension shown in Fig ure 1, the same consists of a plate 4 of conductive material. The superficial area of this plate is so great that regardless of the amount of lateral. deflection on the part of the pole spring to which it is attached, this plate can always be relied upon to make good contact with the terminal 01 the incandescent bulb and never to slip off to theside of said bulb as frequently occurs with the ordinary narrow pole springs. The contact extension is also provided with a plate 6 of insulation material which in the illustrated embodiment of the invention has the form of a square arranged at 90 degrees displacement to the conductive plate 4 so as to provide corners 10 which project laterally on each side of the extension constituting insulation butters which prevent accidental contact oi the plate 4 or of the pole spring itself with the lateral. walls of the Hush light casing, not shown, but which are in general, of corresponding shape to that of the battery. In the drawing'the front corner of the square is cut oil, merely for convenience,this feature being altogether immaterial to the invention.

The corners of the conductive plate 4 are bent around so as to underlie the insulation plate 6 as is shown in Figure 1 thus tying the conductive and insulation plates together into a unitary whole and thereby providing a space between said plates within which the end of the pole spring 2 be slidably forced in the act of mounting said extension upon the pole spring. It is obvious that either one or both out the pole springs 2 or 3 may be provided with a contact extension of this type, that the contact extension so made may be removed or applied to the pole spring without tools and that it may be repeatedly applied to fresh batteries when the batteries are renewed.

In that form of the invention illustrated in Figure 2 the extension takes the form of an elongated conductive plate 4 the forward port-ion of which is widened to afford a wide superficial area for exactly the same purpose as is done in connection with the modification already described. In this case, however, a narrow strip 6 of insulation substance is provided about which the forward end of the conductive plate 4 is anguarly bent as shown at 11 in Figure 4, said insulation strip being in this manner unitarily retained by the conductive plate. The insulation strip 6' is of such length as to extend laterally beyond the edges of the conductive plate 4 so as to prevent accidcntal contact of the conductive plate with the sides of the flash lamp casing.

The rearward portion of the conductive plate 4 is provided with lugs 7 as shown in Fig. 7 adapted to be bent about the pole spring 2 forming a socket for retainmg the extension upon the pole spring. 1t Wlll be noted from Figures 1, 2 and 3 that the pole springs are of that type having a downwardly struck projection or teat 9, as shown in Fig. 3. This is made use or" in that form of the invention shown in Figure 2 to prevent the contact extension slipping endwise from the pole spring. To accomplish this purpose the lugs 7 are notched, preferably with semicircular notches indicated at 8 in Figure 7, these notches registering with the opposite sideso'f the teat- 9, shown in Fig. 3 together surrounding the same so as to hold the contact extension from longitudinal displacement.

Figures 5, 6 and 7 are details and, that form of the invention shown in assembled relation in Figure 4, is particularly adapted as has been stated in the objects of the invention. to the switch means described in my companion application No. 1,590,541 granted June 26, 1926. In this form, the end of the contact extension which engages the pole spring is preferably made in exactly the same manner as that described in connection with Figure 2, that is to say, it includes two lugs 7 notchedas shown at 8 in Figure 7 and surrounding the teat 9 of the pole spring, as shown in Fig. 3. The active end oi the contact extension is preferablybent U-shaped above its soclreted end as shown at 5 in Figures 4 and 6 and the extremity of this bent portion is longitudinally slitted so as to form a tongue 5 which is struck up from the main portion 5 of the spring extension in such a manner as to be depressed under compression in the same direction as is the main portion 5.

The lugs 7 are preferably notched at their ends as shown in Figure 7, so that the device may be applied to the pole spring by pushing it endwise upon the pole spring, the teat 9 engaging the indentation formed by the notches 8 so as to spread the lug sufliciently to permit the device to be slipped into place, the lugs automatically closing around the teat 9.

It is obvious that numerous changes can be made in-the detailed construction of the contact extensions as shown and described without departing from the essence of the invention and that the embodiments shown are therefore to be considered by way of example only and not for the purpose of imposing unnecessary limitations to the scope of the invention, the latter being determined by a liberal construction of the terms of the insulation material carried by said terminal appended claim. to prevent accidental contact between the What I claim is casing of the flash lamp and the metallic 10 An auxiliary terminal for batteries used part of said terminal. 5 in metallic cased flash lamps, having a sock- III mony Wh r f I have Signed my eted portion adapted to be removably slipped name t0 this p ifi ation. over the battery terminal, and a buffer of FRANS ROBERT PAIVIG. 

